Thermoplastic resins have a lower specific gravity than glass or metal and can have excellent mechanical properties such as excellent moldability and impact resistance. Plastic products made using such thermoplastic resins are quickly replacing conventional glass and metal products in fields such as electric and electronic products and automobile components.
There is a growing demand by users for products with a less glossy, or matte, appearance. Especially, materials with low gloss or no gloss are increasingly being used in plastic materials for interior and exterior automobile components, in order to provide a luxurious appearance and touch.
Matte paint can be used to reduce gloss. There can, however, be environmental concerns associated with the same. Also, painting processes can increase production costs.
Conventionally low gloss resins are produced by adding a certain type of rubber substance to the resins or by reforming the resins. However, such methods can be problematic in that they may provide insufficient gloss-reducing effect, and that they may deteriorate impact strength and heat resistance.
As an alternative, a method of graft-polymerizing a monomer such as an ethylene-unsaturated carboxylic acid to a resin has been used. This method, however, can significantly deteriorate heat resistance although providing good overall properties.
Korean patent laid-open publication No. 2009-0029539 relates to a styrene resin composition wherein a syndiotactic polystyrene resin is used as a deglossing agent. This deglossing agent has a three-dimensional syndiotactic structure wherein phenyl radicals or substituted phenyl radicals that are side branches are disposed in opposite directions to one another on a backbone formed by carbon-carbon bonds. Unlike amorphous polystyrene, this type of deglossing agent has crystalline characteristics that make it possible to provide matting characteristics. However, the aforementioned deglossing agent can deteriorate flowability and molding processibility, and thus can deteriorate appearance characteristics and mechanical properties such as impact resistance and the like.
U.S. Pat. No. 4,460,742 relates to a low gloss resin composition including a cross-linked copolymer. Large caliber rubber particles or a matting agent are added to provide a matting effect. However, this can require a large amount of matting agent, can deteriorate impact strength and the like, and also can increase processing costs due to the need to use cast erosion.
Therefore, in order to resolve the aforementioned problems, there is a growing need to develop a thermoplastic resin composition that has excellent matting characteristics while not deteriorating impact strength.